Texas State Technical College DISCOVER! Modeling the Real World Its all about perspective.

Texas State Technical College DISCOVER! Modeling the World Computers are used in the everyday world, thus every computer system must model a real world domain. Accounting Accounting Finance Finance Human Resources Human Resources Inventory Management Inventory Management Sales Sales This applies to databases too. Why model?

Texas State Technical College DISCOVER! Modeling the World The Problem… Modeling the system: Early computer models forced the domain representation to fit a structure that didn’t accurately model the real world. The Solution… Object Oriented Approaches: Model the computer systems after the real world. The Evolution of Modeling

Texas State Technical College DISCOVER! Modeling the World Early Design Approaches Failings: Lack of data encapsulation Lack of data encapsulation All the attributes that described a real world object were separate, independent pieces that had to be tracked. They needed to be packaged together.All the attributes that described a real world object were separate, independent pieces that had to be tracked. They needed to be packaged together. Weak ability to define relationshipsWeak ability to define relationships Since there is no tangible object, how do you define relationships with other non-tangible objects?Since there is no tangible object, how do you define relationships with other non-tangible objects?

Texas State Technical College DISCOVER! Modeling the World Object Oriented Design Key Concept: Everything is viewed and created as independent objects.Everything is viewed and created as independent objects.Implies: Everything is an object, even actions and events.Everything is an object, even actions and events. Each object is a package of attributes (encapsulated), components, and defined relationships to other types of objects.Each object is a package of attributes (encapsulated), components, and defined relationships to other types of objects.

Texas State Technical College DISCOVER! Modeling the World Object Oriented Example [Car Engine Simple] Alternator attributes: voltage watts max torque Battery attributes: voltage total voltage charged Engine attributes: max HP max Torque fuel capacity volume contains charges

Texas State Technical College DISCOVER! Modeling the World Object Oriented Example [Car Engine Detailed] Alternator attributes: voltage watts max torque Battery attributes: voltage total voltage charged Engine attributes: max HP max Torque fuel capacity volume contains Terminal attributes: Type: Positive Terminal attributes: Type: Negative Wire attributes: Capacity Resistance Wire attributes: Capacity Resistance contains connected Terminal attributes: Type: Positive Terminal attributes: Type: Negative contains connected

Texas State Technical College DISCOVER! Modeling the World Object Oriented Example [Inventory] Item attributes: size color category Customer attributes: name address Order attributes: Item Identifier Customer Identifier Date Quantity Placed by For Purchase Of

Texas State Technical College DISCOVER! Modeling the World Object Oriented Example [Department of Motor Vehicles] Vehicle attributes: VIN Color Make Year License Plate attributes: Identifier Registration # Year Issued Registrant attributes: SSN Name Age Address Ownership by Identifies Registration attributes: Registrant # Vehicle # Date Registered Date Expired Ownership of

Texas State Technical College DISCOVER! Modeling the World Object Oriented Analysis Most accurate representation of the real world.Most accurate representation of the real world. Allows designers to better model the real world.Allows designers to better model the real world. Leaves control to the designer, simple models will work but can also be as detailed as needed.Leaves control to the designer, simple models will work but can also be as detailed as needed. Flexible enough to be used in the design of any system.Flexible enough to be used in the design of any system. Traditionally used primarily for programming languages.Traditionally used primarily for programming languages. C++C++ JavaJava Database design is best visualized as Object Oriented.Database design is best visualized as Object Oriented.

Texas State Technical College DISCOVER! Modeling the World Relational Databases Are the most common and frequently used means of information storage and organization.Are the most common and frequently used means of information storage and organization. Utilize an object oriented perspective and design.Utilize an object oriented perspective and design. Represent objects through the use of tables. Represent objects through the use of tables. Represent object attributes through the use of fields.Represent object attributes through the use of fields. Represent object relationships through the use of keys.Represent object relationships through the use of keys.

Texas State Technical College DISCOVER! Modeling the World In Summary… Relational databases are the most commonly used.Relational databases are the most commonly used. They utilize an object oriented perspective and design.They utilize an object oriented perspective and design. Object oriented models allow us to better represent the real worldObject oriented models allow us to better represent the real world Object oriented models capture real world objects, their attributes, and their relationships to other objects.Object oriented models capture real world objects, their attributes, and their relationships to other objects. Relational databases actualize the components through the use of tables (objects), fields (attributes), and keys (relationships).Relational databases actualize the components through the use of tables (objects), fields (attributes), and keys (relationships).